1. The Field of the Invention
This invention relates to cuffs for use on transcutaneous or intrabody prosthetic devices at locations where the devices pass through or into a tissue opening site, i.e., a natural or surgically created opening made in the skin or internal body part to accommodate the device. More specifically, the present invention is directed to methods and apparatus for establishing and maintaining more stable interfaces between the cuffed device and the tissue opening site.
2. The Relevant Technology
Many medical situations require relatively long term implantation of a prosthetic device such as a transcutaneous or intrabody catheter. An example of a transcutaneous catheter is a peritoneal catheter used in patients requiring continuous ambulatory peritoneal dialysis (CAPD). An intrabody catheter is a catheter placed entirely within the body such as, for example, a hydrocephalic shunt coursing from the ventricle of the brain to the peritoneum. Such protheses desirably establish and maintain a long-term stable interface with the surrounding tissue and particularly at tissue opening sites, i.e., natural or surgically created openings made in the skin or internal body part to accommodate the prosthesis. Problems with such devices, however, include instability of this prosthesis/tissue opening site interface and accompanying discomfort, prolonged or absent wound healing, and infectious complications which, in a worst case scenario, may prevent proper functioning of the device and/or force removal of the device.
Typically, cuffs, such as DACRON in the form of felts, velours, meshes and weaves, have been utilized at various locations along implanted prosthetic devices, including at the prosthesis/tissue opening site interface, to provide an attachment surface for biointegration with surrounding tissue to thereby stabilize the underlying prosthetic device in a desired position. It has been found, however, particularly at prosthesis/tissue opening site interfaces, that these cuffs may permit contaminants to traverse the site. For example, with CAPD and other transcutaneous catheters, the tissue opening site is generally referred to as the skin exit site. It has been observed that old blood, serum, antiseptic, lint, keratin, etc. tend to accumulate in the portion of the cuff external to the catheter/skin exit site interface. Colonization by bacteria and formation of a bacteria biofilm rapidly occurs within these accumulations. Contamination sometimes progresses through the skin exit site, resulting in a localized exit site infection. Such a local infection can easily become internalized, increasing the difficulty of treatment and the risks to the patient and creating increased morbidity and expense.
With respect to CAPD catheters, for example, infectious complications can be described as falling into several general categories, although it will be appreciated that these problems are interrelated, and may also be thought of as lying along a continuum. Clinical experience has shown that cuffing material, typically DACRON, brought through the skin exit site almost universally becomes an infection site. For this reason, it has become conventional practice to place the DACRON cuff some distance beneath the skin surface, usually 1.0-2.5 cm. Even with this design, however, a common problem is manifested as a fairly localized skin exit site infection, which involves an infection from the location where the catheter enters the skin opening site to, generally speaking, the subcutaneous portion of this first cuff. The next is a tunnel infection, which is an infection involving the first DACRON cuff, if one is applied, and along the tunnel of the subcutaneous course of the uncuffed or underlying catheter up to, or involving, the deep DACRON cuff, which is generally located in the rectus abdominus muscle. Another type of infection is peritonitis, which involves the peritoneal space surrounding the entire catheter within the peritoneum or even beyond the catheter region. It is believed that skin exit site infection can proceed to a tunnel infection and subsequently cause peritonitis, demonstrating the interrelationships of these infections. Many efforts have been directed toward reducing the incidence of skin exit site infection, but little change in infection rates has been observed, despite new advances in cuffing materials, implant techniques and skin exit site care.
Another example of these problems has been observed in connection with artificial heart and heart assist lines, where transcutaneous access is needed for electrical power and possibly venting, or for pneumatic powering of the heart. Here the infection(s) may involve the skin exit site, proceed along the drive line to the pump pocket where it can involve the entire pocket of the pump and subsequently to the valve conduits and vascular grafts. Even though it is rare for these infections to cause the demise of the patient, they do create significant morbidity and expense associated with treatment, and may require operative intervention.
It would be an advancement in the art to provide methods and apparatus permitting establishment and maintenance of a prosthesis/tissue opening site interface with improved stability. In particular, such a stable interface would be less prone to infection and/or wound healing difficulties.
Such methods and apparatus are disclosed and claimed herein.